After trying 31 pound cakes, we found that the perfect version varies the "pound-of-each" formula and relies on an unusual mixing method. For a pound cake recipe that was moist and soft on the one hand but also dense, light, and rich on the other, we discovered a secret: lightly beating the eggs in a bowl and then adding them by the tablespoon to the creamed butter and sugar. Apparently, the butter and sugar mixture is incapable of absorbing whole eggs; the mixture "curdles" and all the air is let out, resulting in tough, shrunken, wet pound cakes. But dribbling in beaten egg a little at a time preserves the emulsion and allows the air to be retained, making for a light, soft, tender cake.